We propose to conduct an 8-year follow-up examination of a population-based sample of 700 young adolescents. The recruitment and baseline exam of this cohort was conducted when they were 5-12 years old. Our overall objective is to assess a wide range of risk factors for and subclinical and clinical consequences of early childhood obesity and sleep problems. Specifically, we propose to evaluate the following three specific aims: 1) the prospective relationships between childhood sleep related factors and obesity in young adulthood; 2a) the longitudinal association between baseline obesity and cardiometabolic, sleep and neurobehavioral outcomes at follow-up; 2b) cross-sectional association between obesity and relevant clinical and subclinical cardiometabolic and sleep abnormalities at follow-up; and 3) whether SDB in adolescence is age-dependent. We plan to assess the independent associations between independent variables in the obesity and sleep domains and three inter-related health outcomes involving cardiometabolic, sleep and neurobehavioral systems. Obesity both in adults and children has become epidemic and is a major public health problem given its association with CVD, the leading cause of death, and other metabolic diseases. However, there are limited data assessing the risk factors for, and outcomes of, childhood obesity. Recent data from our group and others are supportive of a systematic prospective investigation of our hypotheses, and these evidences include: (1) Sleep duration has been recently identified as a novel risk factor for obesity, and the association is modified by factors such as age, gender, stress, physical activity, and socioeconomic status. In our data, we observed a cross-sectional association between sleep duration and obesity based on subjective but not objective reports; (2) Obese adults that are stressed frequently have mild hypercorticolism and are at risk for stress-induced visceral obesity and metabolic syndrome. Our data, from the child and adult samples, support this hypothesis; (3) Obesity in adults is a strong risk factor for cardiovascular disease. In our child sample, we have reported that obesity and SDB are strong and independent risk factor for higher levels of BP and impairment of cardiac autonomic modulation; (4) In adults it is hypothesized that obesity leads to higher risk of CVD via metabolic syndrome pathway and there is increasing concern that metabolic factors are elevated in obese children as well. We and others have reported that SDB in adults is associated with increased risk of the metabolic syndrome. In our child data, SDB was cross-sectionally associated with an increased risk for several metabolic abnormalities; (5) We and others have reported that impaired autonomic modulation is significantly associated with CVD mortality and morbidity. In our children sample, we have reported significant synergistic interactions between SDB-HRV and obesity-HRV on elevated BP, indicative of complex inter-relationships between sleep, obesity, and cardiometabolic health occurring early in life. Finally, in our child data the age distribution of SDB suggested a possible age-dependent relationship within adolescence. PUBLIC HEALTH RELEVANCE: Obesity in childhood has become an epidemic and a major public health problem. This prospective study will assess a wide range of novel risk factors for and subclinical and clinical consequences of early childhood obesity and sleep problems. The knowledge gained from this study will better position our intervention strategies to reduce the public health burden of childhood obesity.